This is how I would handle it. Assuming you have looked over each tractor and by elimination determined they are VERY comparable. Nothing obviously wrong, broken etc.

It sounds like you do not have a strong feeling toward the "look" of the tractor (yellow or red, older or newer style). Or you would not be asking this question

Ok that's fine. I would just go drive them both. Speed a good 15 or 20 minutes driving each one around if you can, go through all the gears and drive them each in the same route. Then base your decision for lack of a better term "By the seat of you pants". Buy which ever one "FEELS better to you.

If you think thats bad, try choosing out of fifteen of them at a auction, each one a little different and having there own characteristics,All going in same price range, give or take . then walk away with out any and KICKING your self" "Jack"